Could this popup saying that I have a fetal trojan be a virus?

Im using a Sprint Samsung Galaxy S4 and when I clicked a link from a friend to see a video, a screen popped up saying the following page was adult content or something. I ignored it and brushed passed without really reading it. It was immediately followed by another that claimed i had a "fetal trojan" (yes, fetal.) And that unless I downloaded DU Speed Booster or something like that within 30 seconds, all my information would be at risk. Im new to smart phones and cant tell if this is a real threat. I have not downloaded anything recently as I dont care to use apps.

The term fetal rather than fatal is a dead giveaway that it's a scam. Unlikely but possible that you downloaded a virus. You can download an antivirus app like Avast to search and clean. Or you can factory reset. Under normal circumstances, android does not need antivirus, but rarely, if you download a suspicious link or app, it can happen.

And NEVER run an app that "cleans RAM". That's great for Windows, but like cyanide for Android. Android WANTS to have RAM filled up - unused RAM is wasted RAM. DU "cleans" the app, Android reloads it, DU recleans it, Android reloads it, etc., etc., slowing the phone down and killing the battery.

DU Booster is one of those apps you should never install. You should install a good (Avast, AVG, even McAfee) antivirus app andMalwarebytes Anti-Malware. (If you have a Samsung, don't install Lookout - you have to disable its main function in a Samsung phone or it'll eat your battery for lunch. They say they're working on that bug.)

Most "your phone has malware" popups are malware. At best, they're PITA (pain-in-the-<you know where>) apps. And, as KCAndroid said, that "fetal trojan virus" is a dead giveaway. 1) It's "fatal". 2) It's either a Trojan (not trojan - it's named after a city, so it's a proper noun, so it gets capitalized in English) or a virus, it's not a Trojan virus - they're different things. And most viruses aren't fatal - which would mean they hard-brick your phone. At worst, they soft-brick it, and most of them don't even do that, they're just a lot of work to get rid of and they may damage or delete some files. Also the app couldn't know where your phone got the virus - an adult site or a government site that's been hacked.